LOS ANGELES— A five-year-old female mountain lion named P-23 has died after she was struck by a vehicle on Malibu Canyon Road in the Santa Monica Mountains. P-23 was beloved by Southern Californians and became famous in 2013 after she was photographed on top of a deer on Mulholland Highway.

“This animal’s tragic death is a reminder that wildlife corridors and open space are critical to the survival of these magnificent cats,” said J.P. Rose, an attorney at the Center for Biological Diversity. “California needs to stop funneling money into more highway projects when our existing road networks don’t include crossings to protect mountain lions and other key members of our ecosystems.”

P-23 is the 18th mountain lion to be killed in a road collision in the region since 2002. Existing freeways and sprawl development in Southern California severely limit mountain lion movement in the Santa Monica and Santa Ana mountains, leading to decreases in genetic diversity.

As these big cats struggle to survive in urbanized Southern California, some local jurisdictions are making the problem worse. The city of Temecula in Riverside County just approved the Altair development in a wildlife corridor that Santa Ana mountain lions rely upon. The Center and other conservation groups filed a lawsuit challenging the Altair project in January.

Environmental groups and local officials have advocated for the Liberty Canyon wildlife crossing over Highway 101, which will improve mountain lion movement in the Santa Monica Mountains if it is built. However, progress has been slow due to lack of funding for the project.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 1.6 million members and online activists dedicated to the protection of endangered species and wild places.